DE10132943A1 - Silane-modified oxidic or silicate filler, process for its production and its use - Google Patents

Abstract

Oxide or silicate fillers modified with a mercapto silane (I) and an alkylsilane (II) and/or with a silicone oil are new. Oxide or silicate fillers modified with a mercapto silane of formula (R<1>)3Si-R<2>-SH (I) and an alkylsilane of formula (R<1>)3Si-R<3> (II) and/or with a silicone oil are new: R<1> = alkoxy or alkyl, at least one being alkoxy; R<2> = a divalent hydrocarbon group; R<3> = (un)saturated alkyl. Independent claims are included for: (1) a process for producing the modified fillers, comprising mixing an oxide or silicate filler with (I) and (II) and/or with a silicone oil; and (2) rubber mixtures comprising rubber, a modified filler as above, and optionally precipitated silica, carbon black and/or other rubber additives.

Description

The invention relates to a silane-modified oxidic or silicate filler, a process for its Manufacturing and its use.

It is known to use oxidic or silicate compounds Treat organosilicon compounds through this Treatment of the bond between the inorganic filler and the organic polymer used in filler-reinforced elastomers and thus the To improve the properties of the fillers in the polymers.

From DE 21 41 159, DE 22 12 239, US 3,978,103 and US 4,048,206 known that sulfur-containing organosilicon compounds, such as Bis- (3-triethoxysilylpropyl) tetrasulfan or 3-mercaptopropyltriethoxysilane, as a silane coupling agent or Reinforcing additive in oxidically filled rubber compounds, among other things for treads and other parts of car tires, be used. The use of mercaptosilanes in Rubber compounds for tire treads is out FR-A 152.094.859 known. To the significant problems with the Processing, such as pre-scorch and Plasticity behavior to bypass mercaptosilanes, is usually used as a coupling agent for tire parts polysulfidic organosilanes, such as that Bis (3-triethoxysilylpropyl) tetrasulfan or that Bis- (3-triethoxysilylpropyl) disulfane (DE 25 42 534, DE 24 05 758, DE 195 41 404, DE 197 34 295), which is the best compromise for silica-filled vulcanizates with regard to Vulcanization security, easy manufacture and Offer reinforcement performance.

The introduction of the appropriate additives, especially the Organosilanes and the unmodified fillers in the unvulcanized polymer blends can be found on different because of. The in-situ process includes one common mixing process of fillers such as carbon black and Silica, organosilanes and polymer.

The ex situ procedure involves a modification of the Filler with the corresponding organosilane or one Mix of different organosilanes before the filler is mixed with the polymer.

It is known that by dissolving the Organosilicon compound in an organic solvent and subsequent treatment of fillers, for example Clays, the filler surface can be modified (U.S. Patent 3,227,675).

Nowadays, this plays a particularly important role Liquid dosage (US 3,997,356) or the dosage of active filler via a pre-formed mixture Organosilane and filler (DE 33 14 742, US A-4 076 550). Disadvantages of these thermally not pretreated blends is the lack of storage stability and thus the lack Property stability of the products.

U.S. Patent 4,151,154 describes oxidic silicate Fillers, the surface of which is treated with two different types of organosilicon compounds is exposed. The oxide particles become like this treats them to have a greater affinity for water and can also be more easily distributed in aqueous systems.

From US-PS-35,67,680 is the modification of in water suspended kaolin known with various silanes. The Organosilicon compounds described are, however, in the Amounts necessary for the modification water-soluble, so that in in this case the treatment of the filler from an aqueous Solution can be done.

FR-A-2295958 relates to and with aryl polysulfides Mineral fillers treated in compounds Rubber compounds are used. The production takes place in an aqueous / alcoholic formulation containing 99.9 to 80% by weight Contains alcohol.

Furthermore, from EP-PS 01 26 871 a method is known in which the surface of silicate fillers with the help of a aqueous emulsion of water-insoluble Organosilicon compounds modified.

The known silane-modified fillers have the Disadvantage that the dynamic properties are not better than those of the in-situ mixed fillers and silanes.

The object of the present invention is a silane-modified oxidic or silicate filler produce a homogeneous surface coverage and the improved dynamic properties in Rubber, as rubber mixtures made in-situ has.

The invention relates to a silane-modified oxidic or silicate filler, which is characterized in that at least one oxidic or silicate filler with a mercaptosilane of the general formula (I)

(R ¹ ) ₃ Si-R ² -SH I

wherein the substituents R ^{1 are} identical or different and consist of alkoxy, preferably methoxy, ethoxy or propoxy, or alkyl, where at least one group R ^{1 is} an alkoxy group, R ^{2 is} a divalent alkyl radical, preferably methylene, ethylene or propylene,
and an alkylsilane of the general formula (II)

(R ¹ ) ₃ Si-R ³ II

wherein R ^{3 is} a saturated or unsaturated, branched or unbranched alkyl radical, and / or is modified with silicone oil.

The silane-modified oxidic or silicate filler can be between 0.1 and 50.0% by weight, preferably between 1.0 and 25.0% by weight, particularly preferably between 1.0 and 8.0% by weight, Mercaptosilane and alkylsilane and / or silicone oil contain.

The silanes can chemically or physically with the Surface of the filler to be connected.

Another object of the invention is a method for Production of the silane-modified according to the invention oxidic or silicate filler, which thereby is characterized in that at least one oxidic or silicate filler with a mercaptosilane of formula I. and an alkylsilane of formula II and / or with silicone oil mixed.

The reaction can be carried out with or without a solvent, for example methanol, ethanol, pentane, hexane, cyclohexane or toluene.

The oxidic or silicate filler can first with the Mercaptosilane and then with the alkylsilane and / or silicone oil be mixed or vice versa. The mercaptosilane and that Alkyl silane and / or silicone oil can be mixed first and then with the oxidic or silicate Filler can be mixed.

The mercaptosilane and alkysilane and / or silicone oil can Spray on the oxidic or silicate filler. The spraying can preferably be carried out at 10-50 ° C become. The implementation, that is, the reaction of the silanes with silica, can be at temperatures from 50 ° to 200 ° C, preferably 60 ° to 160 ° C, take place. Implementation at elevated temperature can be applied immediately after spraying (one-step) or in separate steps (two-step).

The implementation can take between 1 and 200 minutes, preferably 1 and 30 minutes.

The oxidic or silicate filler and that Mercaptosilane and alkylsilane and / or silicone oil can continuously circulated with a suitable stirring unit become. The stirring speed of the temperature be adjusted.

Stirrers, blade stirrers, bar stirrers, Perforated bar stirrer, cross bar stirrer, anchor stirrer, Lattice stirrer, paddle roller, propeller stirrer, screw stirrer, Turbine stirrer, disc stirrer, planetary stirrer, rotary mixer or impeller stirrer can be used.

The agitator can with 1-200 revolutions, lifting movements or circulations per minute.

Following the surface modification, the silane modified oxidic or silicate filler be annealed. The temperatures can be 50 ° to 200 ° C, preferably 50 ° to 160 ° C.

As mercaptosilane, compounds of the general formula (I)

(R ¹ ) ₃ Si-R ² -SH I

where substituents R ^{1 are} identical or different and consist of alkoxy, preferably methoxy, ethoxy or propoxy, or alkyl, where at least one group R ^{1 is} an alkoxy group, R ^{2 is} a divalent alkyl radical, preferably methylene, ethylene or propylene , Mercaptopropyltrimethoxysilane, mercaptopropyltriethoxysilane, mercaptoethyltrimethoxysilane or mercaptoethyltriethoxysilane can preferably be used as mercaptosilanes.

Compounds of the general formula (II)

(R ¹ ) ₃ Si-R ³ II

where R ^{3 is} a saturated or unsaturated, branched or unbranched alkyl radical can be used.

As alkylsilanes, propyltriethoxysilane, Butyltriethoxysilane, pentyltriethoxysilane, Hexyltriethoxysilane, heptyltriethoxysilane, Octyltriethoxysilane, hexadecyltriethoxysilane, Octadecyltriethoxysilane, propyltrimethoxysilane, Butyltrimethoxysilane, pentyltrimethoxysilane, Hexyltrimethoxysilane, heptyltrimethoxysilane, Octyltrimethoxysilane, hexadecyltrimethoxysilane or Octadecyltrimethoxysilane can be used.

Aluminum silicate, silicate, precipitated or pyrogenic silica with BET surfaces (measured with gaseous nitrogen) of 1 to 1000 m ² / g, preferably up to 300 m ² / g, can be used as the oxidic or silicate filler.

For example, those of Degussa-Hüls AG under the Trade name Ultrasil precipitated silicas (Ultrasil 7000, Ultrasil 7000 GR, Ultrasil VN 3, Ultrasil VN 3 GR, Ultrasil VN 2 and Ultrasil VN 2 GR) can be used.

Another object of the invention are Rubber mixtures, which are characterized in that they rubber, the silane-modified according to the invention oxidic or silicate filler, if necessary precipitated silica and / or soot and / or others Contain rubber auxiliaries.

In addition to natural rubber, synthetic rubbers are also suitable for the production of the rubber mixtures according to the invention. Preferred synthetic rubbers are described, for example, by W. Hofmann, Kautschuktechnologie, Genter Verlag, Stuttgart 1980. They include, among others
Polybutadiene (BR),
Polyisoprene (IR),
Styrene / butadiene copolymers with styrene contents of 1 to 60, preferably 5 to 50% by weight (E- or S-SBR),
Isobutylene / isoprene copolymers (IIR),
Butadiene / acrylonitrile copolymers with acrylonitrile contents of 5 to 60, preferably 10 to 50% by weight (NBR),
Ethylene / propylene / diene copolymers (EPDM),
as well as mixtures of these rubbers.

The rubber mixtures according to the invention can be further Auxiliary rubber products such as Reaction accelerators, retarders, anti-aging agents, Stabilizers, processing aids, plasticizers, waxes, Metal oxides and activators, such as triethanolamine, Contain polyethylene glycol, hexanetriol.

The rubber auxiliaries can be used in conventional amounts among other things, according to the intended use become. Usual amounts are, for example, amounts from 0.1 to 50% by weight, based on rubber.

Sulfur, organic sulfur donors or Radical formers are used. The invention Rubber compounds can also be used Vulcanization accelerator included.

Examples of suitable vulcanization accelerators are Mercaptobenzthiazoles, sulfenamides, guanidines, thiurams, Dithiocarbamates, thioureas and thiocarbonates.

The vulcanization accelerators and crosslinkers can be used in quantities from 0.1 to 10% by weight, preferably 0.1 to 5% by weight, based on Rubber.

The mixing of the rubbers with the filler, optionally rubber auxiliaries and the organosilanes can in conventional mixing units, such as rollers, internal mixers and Mixing extruders are carried out. Usually will such rubber mixtures made in internal mixers, where initially in one or more consecutive thermomechanical mixing stages the rubbers, the silane-modified oxidic or silicate according to the invention Filler, optionally the carbon black and / or the silica and / or further rubber auxiliaries at temperatures of 100 can be mixed in up to 170 ° C. The can Order of addition and the time of addition of Individual components crucial to the received Mix properties affect. The so obtained Rubber mixture is then usually in one Internal mixer or on a roller at 40-110 ° C with the Crosslinking chemicals added and the so-called Raw mix for the subsequent process steps, such as Example shaping and vulcanization, processed.

The vulcanization of the rubber mixtures according to the invention can at temperatures from 80 to 200 ° C, preferably from 130 to 180 ° C, optionally under pressure of 10 to 200 bar.

The rubber mixtures according to the invention are suitable for Manufacture of moldings, for example for the manufacture of pneumatic tires, tire treads, cable sheaths, tubes, Driving belts, conveyor belts, roller coverings, tires, shoe soles, Sealing rings, profiles and damping elements.

The oxide or silane modified according to the invention silicate fillers point towards the in-situ Mixtures take advantage of lower viscosity, higher ones Module and improved dynamic properties.

Examples example 1 Production of the silane-modified oxidic or silicate filler B1

In a Henschel mixer, 3000 g of Ultrasil 7000 GR submitted. 74 g of mercaptopropyltrimethoxysilane (Si 163) and 112.5 g of octyltriethoxysilane (Si 208) in succession, at Temperatures of 23 ° C sprayed on with stirring. Subsequently the material is removed from the Henschel mixer and this heated to 120 ° C. Then the silica Mix the silane in the hot mixer and stir Reacted for 30 minutes at 120 ° C.

Example 2 Production of the silane-modified oxidic or silicate filler B2

In a Henschel mixer, 3000 g of Ultrasil 7000 GR submitted. 74 g of mercaptopropyltrimethoxysilane (Si 163) and 112.5 g octyltriethoxysilane (Si 208) in 400 g ethanol solved. The silane solution is at temperatures of 23 ° C on the Ultrasil 7000 GR sprayed on with stirring. Then will removed the material from the Henschel mixer and opened it Heated to 120 ° C. Then the silica-silane mixture in filled the hot mixer and with stirring for 30 minutes 120 ° C fully reacted.

Example 3 Rubber-technical investigation of the silane-modified oxidic or silicate fillers

The formulation used for the rubber compounds is given in Table 1 below. The unit phr means parts by weight, based on 100 parts of the raw rubber used. The general process for the production of rubber mixtures and their vulcanizates is described in the book: "Rubber Technology Handbook", W. Hofmann, Hanser Verlag 1994. Table 1

The polymer VSL 5025-1 is a in solution polymerized SBR copolymer from Bayer AG with a Styrene content of 25 wt .-% and a butadiene content of 75% by weight. Of the butadiene, 73% are 1.2, 10% cis 1.4 and 17% trans 1.4 linked. The copolymer contains 37.5 phr of oil and has a Mooney viscosity (ML 1 + 4/100 ° C) of 50 ± 4.

The polymer Buna CB 24 is a cis 1,4-polybutadiene (neodymium type) from Bayer AG with cis 1,4-content of 97%, a trans 1,4-content of 2%, a 1,2-content of 1% and a Mooney viscosity of 44 ± 5.

Naftolen ZD from Chemetall is used as the aromatic oil. Vulkanox 4020 is 6PPD from Bayer AG and Protector G35P is an ozone protection wax from HB-Fuller GmbH. Vulkacit D (DPG) and Vulkazit CZ (CBS) are commercial products Bayer AG.

Ultrasil 7000 GR is a well dispersible precipitated silica from Degussa AG with a BET surface area of 170 m ² / g. Si 163, mercaptopropyltrimethoxysilane and Si 208, octyltriethoxysilane are commercial products of Degussa AG.

The rubber mixtures are produced in an internal mixer in accordance with the mixing instructions in Table 2. Table 2

Table 3 lists the methods for rubber testing. Table 3

Table 4 shows the results of the rubber test. The mixtures are vulcanized at 165 ° C for 20 min. Table 4

As can be seen from the data in Table 4, that is Gum value image of the mixture (2 + 3) with the invention silane-modified oxidic or silicate fillers above that of the in-situ reference (1). Among other things, the shorter t10% times, the lower Mooney viscosity that higher voltage values and the lower tanδ (60 ° C) value an improvement over the in-situ mix.

Claims (8)

1. Silane-modified oxidic or silicate filler, characterized in that at least one oxidic or silicate filler with a mercaptosilane of the general formula (I)

(R ¹ ) ₃ Si-R ² -SH I

where the substituents R ^{1 are} identical or different and consist of alkoxy or alkyl, where at least one group R ^{1 is} an alkoxy group, R ^{2 is} a divalent alkyl radical,
and an alkylsilane of the general formula (II)

(R ¹ ) ₃ Si-R ³ II

wherein R ^{3 is} a saturated or unsaturated, branched or unbranched alkyl radical, and / or is modified with silicone oil. 2. Silane-modified oxidic or silicate filler according to claim 1, characterized in that this between 0.1 and 50.0% by weight of mercaptosilane and alkylsilane and / or Contains silicone oil. 3. Process for the preparation of the silane-modified, oxidic or silicate filler according to claim 1, characterized characterized in that at least one oxidic or silicate filler with a mercaptosilane of formula I. and an alkylsilane of formula II and / or with silicone oil mixed. 4. Process for the preparation of the silane-modified, oxidic or silicate filler according to claim 3, characterized characterized in that the reaction without solvent performs. 5. Process for the preparation of the silane-modified, oxidic or silicate filler according to claim 3, characterized characterized in that the reaction in a solvent performs. 6. Process for the preparation of the silane-modified, oxidic or silicate filler according to claim 3, characterized characterized in that a temperature between 0 and 200 ° C. comply. 7. rubber mixtures, characterized in that they Rubber, the silane-modified according to the invention oxidic or silicate filler according to claim 1, optionally precipitated silica and / or soot and / or contain further rubber auxiliaries. 8. Use of the rubber mixtures according to claim 7 for Manufacture of molded articles.